Since
autumn of 2016, the cryptogenic parasite Haplosporidium
pinnae has caused an unprecedented mass mortality event of the protected
endemic Mediterranean bivalve Pinna
nobilis in the western Mediterranean Sea.

This study
confirms the spread of the parasite in the eastern Mediterranean and provides
the direct evidence on the collapse of the P.
nobilis populations in the coastal waters of Lesvos Island (Aegean Sea,
Greece). The presence of the parasite was confirmed through histopathological
and molecular methods.

While the
infection caused >93% of mortality in most sites, the authors highlight that
in a single site (among 13 surveyed sites) mortality was relatively low and the
parasite was not detected. It is underpinned that this observation stresses the
importance of possible parasite-free refugia sites.

In front of
the worrying spread of this infection, the authors call for continuous
monitoring of the spread of the parasite and its impacts, and for urgent
targeted research and actions to identify the factors affecting the parasite’s
virulence, investigate biotic and abiotic conditions that characterize refugia
sites, and strictly protect the remaining P.
nobilis populations to increase the chance for the survival of the species.